Brian Hillins wrote:

I moved into a house in June and since that time have notice a water
puddle that forms in the middle of my basement on occasion. I have
tried to find a trend with when the water forms and cannot find any.
The water has formed in the summer, the fall, and now the winter
(despite the frozen ground in Minnesota).

I feel your pain. I had this problem myself and it turned out to be
a $$very expensive$$ fix.


My next step was to look for internal sources creating this water.
After trying every appliance, drain, facet, and bathroom, I cannot
find the source of the leak. I even placed a pan on the puddle and
found that the water is forming from below the concrete (the pan was
dry but under the pan was not).

Did you try pouring a bottle of dye down a drain, flushing it down
with water, waiting several hours, then checking the color of the
water on the floor? Obviously you do this to just one drain at a
time, and wait a day or two before trying the next line, but that's
how I determined my floor puddles were coming from the kitchen drain
pipe, which had apparently developed one or more breaks under the
basement floor.

After dealing with this for several months I finally decided to take
action. Having some knowledge of the workings of the house my
assumption was that the soil pipe from the kitchen and washer/dryer
which cuts beneth the floor to the main sewer return on the other side
of the house must be leaking. I scored the concrete floor and created
a 3 by 4 foot rectangular hole in the concrete floor. I expected to
see moisture in the soil at the very least and was quite shocked when
this was not the case. I tried digging down about 8 inches to find
the pipe and was unsuccessful. I hit clay and figured that I must be
deep enough.

Not finding the pipe is not necessarily a big surprise. It can be
very difficult to trace the route of the pipe under the cement
floor. In my case I was only able to trace it from within a few feet
of where it started by the wall, and unfortunately my uncle who'd
done the plumbing back in '54 when my house was built is no longer
alive. We (the plumber and I) ended up trenching in the direction we
logically assumed the pipe had to have been laid - and we were
wrong. We finally gave up trying to find the rest of the run,
re-started at the main sewer line, cut back to our trench, and laid
a new drain.

I just had another plumber in my basement this afternoon installing
a water heater. He noticed the trench and we swapped hunt-the-line
stories. According to him, you just can't conclude the drain line
*must* run where you think it'd make sense to run - he's seen too
many situations where it didn't conform to any logical deductions.
So you might have simply excavated in the wrong place.

So my questions are as follows:
1) How deep do they burying the soil pipes beneath the concrete of a
house? Minnesota house built in 1949? (More detail: I am about 6 or
7 feet from the main return line and about 15 feet from the kitchen
return line and washer/dryer line)

Considering the depth of the basement, they needn't go much deeper
under the floor. I don't think the main waste pipe in my house (also
Minnesota, built in '54) was more than 2 feet down at the most, and
so the runs from the sinks etc would start a little shallower and
gradually drop to meet with the main line, or with another line that
connects to it.

2) I am thinking that my best course of action is to find that pipe
and determine if this is the source of the water, should I be trying
or thinking of something else?

See the dye suggestion above. I went to a craft store and bought
small bottles of food coloring for cake decorating - that dye is
very potent indeed, so it was easy to spot the tint in the water.
Though it was extremely depressing to have that prove it was a
plumbing break. I think if it had just been ground water responding
to hydrostatic pressure, I'd have sighed and lived with it.

HTH,

HellT